for the Microscope. 65 



469. JENNER'S SPIRILLUM (Spirillum Jennert). This is 

 a rare species, and is given as an illustration of the group 

 to which it belongs. The filaments are green, and found 

 mixed with Oscillatoria. They form a loose spiral, and 

 are apparently beaded, from the numerous divisions. (PI. 

 VI., fig. 19.) 



470. HEATH CONFERVA (Zygogonium cricetorum}. In 

 appearance confervoid ; the filaments forming a stratum 

 on swampy heaths, and sometimes in water, of a dull 

 purplish colour. The cells about twice as long as broad. 

 (PL VI., fig. 20.) 



471. BANDED CONFERVA (Ulothrix zonata). Filamen- 

 tous, bright green, delighting in clear water and the 

 neighbourhood of w r aterfalls. Cells rather longer than 

 broad, or not half as long as broad, almost cylindrical, 

 with a clear margin around them. Common. (PI. VI., 

 fig. 21.) 



472. WALL CONFERVA (Lyngbya muralis). Common 

 on damp walls, and conspicuous after a shower of rain. 

 Filaments entangled, contorted, dark green ; cells short. 



473. SPORE OF CONFERVA (Spirogyra sp.). The spore 

 (analogous to seed) of a species of Spirogyra, with its 

 spiral fibre in the interior, just before germination, is 

 shown in the figure. (PL VI., fig. 23.) 



474. Mucous CONFERVA (Ulothrix mucosa). Found 

 in stagnant water. The filaments are surrounded by a 

 mucous envelope. - Similar to No. 471, but not so com- 

 mon. (PL VI., fig. 24.) 



475. SPERMATOZOIDS. These curious bodies are more 

 or less common amongst algae, varying a little in shape. 

 Often ovate, with two or more active cilia at the narrow 

 end. They issue from special receptacles, and are the 

 agents of fertilization. (PL VI., fig. 25.) 



476. SPIRAL CONFERVA (Spirogyra commune). The 

 spiral arrangement of the green contents of the cells is 

 common to several species of Conferva, of which this is 

 an example not uncommon in ponds. (PL VI., fig. 26.) 



477. ELLIPTIC SPHJEROZYGA (Sphcerozyga leptosperma). 

 The filaments are slender and jointed, collected into a 



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